Abstract: A system and a method for encoding and decoding ultra-wideband information are provided. An ultra-wideband transmission is encoded by positioning bipolar pulse pairs. The bipolar pulse pairs assist in detecting errors in the ultra-wideband transmission, before the entire transmission has been received. The transmission is analyzed for errors and an error rate is calculated. The calculated error rate is compared to one or more predefined acceptable error rate levels to determine whether the calculated error rate of the transmission is within at least one of the predefined acceptable error rate levels.

Abstract: An IC card is set to an RF mode by default when drive electric power starts being applied to the IC card. When both a clock signal and a reset signal are applied to respective connection terminals, the IC card switches to a terminal mode. The clock signal and the reset signal that are applied to the respective connection terminals can be detected without the need for an analog circuit such as a comparator. The IC card can be switched between the terminal mode in which only input signals applied to the connection terminals are effective and the RF mode in which only an input signal applied to a radio antenna is reliably effective, with only a digital circuit.

Abstract: A skew correction apparatus for increasing the data transfer capacity and thus improving the system performance, by making it possible to carry out the deskew work even during the data transfer, is disclosed. The skew correction apparatus receives a plurality of serial data in synchronism, and reduces the skew mount constituting a phase shift between the serial data. A first correction unit (31) detects a skew between the serial data and corrects the skew during the idle time. A second skew correction unit (32) detects a skew between the serial data and corrects the skew during the data transmission.

Abstract: A communication system economically mitigates the frequency-selective multipath effects and co-channel interference in wireless LANS. The communication system comprising a wireless local area network (LAN) formed by a plurality of spacially separated transceivers (TR, TR?). Each of the transceivers has a transmitting section (10) for transmitting data by a combination of dual code spread spectrum techniques and a receiving section (12) for recovering the data. The receiving section (12) comprises a plurality of diversity antennas (ANT 1 to ANT n), an adaptive forward equal gain combiner (60) having a plurality of branches (62 to 74 and 62? to 74?), each branch being coupled to a respective one of the diversity antennas. The adaptive forward equal gain combiner (60) selects a signal in one of the branches as a reference signal and co-phases the signals in the remaining branches with the reference signal.

Abstract: The method and device according to the present invention provides a control system, method and apparatus for synchronizing a reference signal to high frequency data signals. Pulses are accumulated before reaching the integrator. Pulse accumulation is provided in a DLL clock and data recovery circuit. Pulses are accumulated using a ripple divider for rising transitions only. In another exemplary embodiment, pulses are accumulated using a ripple divider for both rising and falling transitions.

Abstract: An apparatus, method and system are provided for correlated noise reduction, in a trellis decoding environment, such as second generation HDSL, in which crosstalk impairments may be significant. The preferred embodiments provide equalization and correlated noise reduction, utilizing a training period to generate corresponding coefficients, and utilizing two different training error signals. In addition, the apparatus method and system also provide continued and adaptive correlated noise reduction during data transmission, utilizing two additional error signals, a trellis error signal and a tentative error signal. The trellis error signal is a decision error of a selected previous state of a selected trellis path, in which the selected trellis path has a smallest cumulative error of a plurality of trellis paths, and the selected previous state is preferably the immediately previous state.

Abstract: A signal processing circuit used in a hard disk controller is able to quickly match its clock signal with preamble data read from a hard disk. The signal processing circuit includes a decision feedback equalizer (DFE) that equalizes a digital read signal in accordance with a clock signal. A timing recovery PLL generates the clock signal having a phase which is coincident with a phase of the digital read signal. The DFE includes a first filter for filtering the digital signal, a decision circuit for adding a feedback signal to the filtered digital signal and generating a decision signal based on the value of the addition. A shift register is connected to the decision circuit and samples the decision signal in accordance with the clock signal, and stores the sampled signal as sampling data. A feedback filter filters the sampled data and feeds it back to the decision circuit.

Abstract: A power efficient and reduced electromagnetic interference (EMI) emissions multi-transmitter system for unshielded twisted pair (UTP) data communication applications. For each transmitter, digital transmit data is converted to a current-mode differential signal analog waveform by a digital-to-analog converter (DAC). The output current from each DAC is used to generate the required transmit voltage on the respective UTP line. Timing circuitry staggers the time base of each transmitter to reduce the aggregate EMI emissions of the multi-transmitter system.

Abstract: A method and a device for decoding for use in a code-division multiple access (CDMA) transmission system for demodulating a received signal available in serial code concatenation, with a two-step coding being carried out at the transmitting end of the transmission system, including an orthogonal, multi-step inner Hadamard code and an outer, error-correcting code of a predefined rate. In the receiver, a soft-in/soft-out decoder is provided, at whose input and output soft values are processed as reliability information, i.e., L-values. The soft output of the first decoder step, or inner code is the soft input for the decoder step, or outer code, that follows in each case, the first decoder step receiving the output values of the preceding demodulation, which contain the channel's reliability information. A soft output is used by the decoder, in particular a MAP decoder, as a-priori information for the systematic bits of the Walsh function of the inner code for decoding of the inner code.

Abstract: In a fiberoptical network, for example in a LAN, spread spectrum modulation is used, for example, CDMA, by providing an electrical digital data signal to a spreading device including a multiplier also receiving the spreading code. Then a modulation is made of the spread signal at radio frequencies, the signal being multiplied by a subcarrier wave generated in a oscillator, whereby the data signal is carried on an RF subcarrier. A control channel signal from a control unit is added to the modulated signal, so that the control signal will be located in the baseband. The added signal is converted to an optical signal transmitted on an output fiber. The control channel signal can be TDMA-modulated using collision detection. Making spectrum spreading in the electrical domain allows the use of standard components developed for example for mobile telephone systems. No wavelength control and no optical filters are necessary, which allows a low cost system to be constructed.

Abstract: A pulse-shape estimator calculates an impulse response for the transmit and receive pulse-shaping filters in a mobile wireless terminal. The pulse-shape estimator receives a training signal that has passed through the pulse-shaping filters and known training symbols. Based on the actual received signal containing the training symbols and the expected received signal, the pulse-shape estimator estimates the impulse response of the pulse-shaping filters. The calculated impulse response may be used to improve signal demodulation or to calculate the coefficients for a digital filter applied before demodulation to compensate for pulse-shape distortion.

Abstract: An apparatus comprising a first circuit and a second circuit. The first circuit may be configured to present a parallel output data signal in response to (i) a first clock signal and (ii) one or more serial data signals. The second circuit may be configured to present the one or more serial data signals and the first clock signal in response to (i) a second clock signal and (ii) a parallel input data signal.

Abstract: A system and method for encoding/decoding data channels in a CDMA system having data channel interference cancellation, wherein data channel interference cancellation is used to remove unwanted non-orthogonal pilot signal components which are present within a demodulated data signal. This is accomplished by regenerating interference terms with respect to the non-orthogonal pilot signal and subtracting them from the demodulated data signal.

Abstract: Signal processing operations are performed in a digital communication system receiver on a sequence of received symbols, each representing a number of information bits. The symbols correspond to points in a given modulation constellation generated by applying a predetermined rotation, e.g., a 45° rotation, to an otherwise conventional modulation constellation, e.g., a QPSK constellation, a 16-QAM constellation, etc. The use of the rotated constellation allows certain signal processing operations, such as filtering, Least-Mean-Squares (LMS) estimation, and Maximum-Likelihood (ML) sequence detection via the Viterbi algorithm, to be performed without the need for multipliers. By eliminating or substantially reducing the number of required multiplication operations, the invention significantly reduces the complexity and delay associated with the corresponding signal processing circuitry.

Abstract: In an interpolation synchronous detection method in a radio communication system in which a pilot symbol whose phase point is known is periodically inserted in an information signal to allow interpolation synchronous detection on a receiving side, synchronous detection of the information between the pilot symbols is performed by linearly interpolating a transfer function estimated from the pilot symbols respectively located before and after the information signal, and a reception sampling point timing used for the synchronous detection is updated at the middle point between the pilot symbols respectively located before and after the information signal. A radio communication system is also disclosed.

Abstract: A method and apparatus for quality of service localization within a relatively time-invariant communications network, the method comprising the steps of: receiving quality of service estimations for a plurality of communications mediums, wherein each of the plurality of communications mediums is defined between a respective one of a plurality of transmitters located within the communications network to a common receiving point of the communications network, wherein each communications medium is conveyed over at least one shared physical communications path and at least one non-shared communications path; and comparing the quality of service estimations for the plurality of communications mediums with one another in order to localize a respective quality of service estimation to a likely physical communication path within the communications network.

Abstract: A quadrature device 1 for a communication device, receiver, transmitter, transceiver, telephone, mixer, modulator or demodulator comprises I and Q signal paths and corresponding signal paths components 2I, 2Q; 4I, 4Q; 9I, 9Q showing a mismatch. The device 1 comprises switching circuitry 3, 3?, 6, 3?, 3?? for data dependently exchanging the I and Q signals in the I and Q paths in order to improve adverse effects, such as reduction of leakage of quantisation noise from the image band to the signal band in a quadrature modulator. Even mismatch effects between digital to analog converters (DAC's) in a feedback path of a sigma delta (??) modulator are compensated.

Abstract: A pulse transmitter includes a phase correction module configured for detecting a phase error between a transmit clock and a prescribed clock specification at a transmit clock instance. The transmit clock instance represents an instance in time in which the pulse transmitter is to transmit data according to the prescribed clock specification. The pulse transmitter also includes pulse shape tables, each configured for outputting a corresponding waveform sample set of a prescribed waveform relative to a corresponding phase offset. Hence, the pulse transmitter is able to compensate for phase differences between the transmit clock utilized by the pulse transmitter and the prescribed clock specification, by outputting a selected waveform sample set that has a corresponding phase offset that compensates for the detected phase error, optimizing the performance of pulse position modulation communications systems that are adversely affected by transmit jitter.

Abstract: Decoding signals represented by a trellis of block length N divided into windows of length L includes a step of decoding a forward recursion from a point P that is before the beginning of a window up to the beginning of the window. P is chosen at a sufficient distance from the beginning of the window such that forward recursion determines a known state metric at the beginning of the window. A next step includes decoding the window using forward recursion from the known state at the beginning of the window up to the end of the window to define a set of known forward recursion state metrics which are stored. A next step includes decoding using backward recursion starting from a known state at the end of the window and moving backward. A next step includes calculating a soft output at each stage of the backward recursion using the stored forward recursion state metrics, and branch metrics at each stage, and outputting the soft output for that stage in a LIFO format.

Abstract: An efficient system for determining if a paging channel should be received and processed adapted for use a wireless communications device in a wireless communications system employing a quick paging channel. The system includes a first mechanism for receiving an electromagnetic signal having both pilot signal and quick paging signal components. A second mechanism provides one or more initial quality parameters (Epilot1/Îo1,Epilot1) indicative of a quality of a signal environment in which the electromagnetic signal is propagating. The one or more initial quality parameters are based on the pilot signal and are associated with a first symbol of the quick paging signal. A third mechanism ascertains whether a second symbol of the quick paging channel signal or the subsequent paging channel should be processed based on the one or more initial quality parameters and provides a first indication in response thereto.